Device for applying cover sheets on palletized loads

ABSTRACT

A device for applying cover sheets on palletized loads, including at least one support for at least one palletized load, means for unwinding at least one reel of cover film from which a plurality of sheets to be applied on the palletized loads can be obtained, and at least one applicator member suitable for positioning, one-by-one, the cover sheets obtained from said reel on the top of respective palletized loads. The applicator member includes at least one robotic arm having at least one operative end with which at least one grip member is associated, said grip member being suitable to pick up each cover sheet unwound from said reel at least one edge, and to position it on the top of a respective palletized load.

TECHNICAL FIELD OF THE INVENTION

The present invention regards a device for applying cover sheets onpalletized loads.

In particular, the present invention regards a device for applying uppercover sheets on palletized loads, on which the automated wrapping isexecuted in wrapping machines.

DESCRIPTION OF RELATED ART

In the packaging field, the palletized loads, i.e. the articles stackedon load pallets, are wrapped by automatic wrapping machines withsuitable packaging films, so as to easily allow the transport of thearticles and preserve the integrity thereof.

Such wrapping machines also comprise devices which apply cover sheets onthe top of the palletized loads to be wrapped, so as to protect themfrom water or dust which could otherwise be deposited and/or penetratewithin the loads themselves. The wrapping machines can be of varioustype, e.g. with rotary table that supports the load to be wrapped, or ofanother type; depending on whether the wrapping of the palletized loadmust be anti-dust or anti-water, the film is wound around the loaditself according to different modes.

More in detail, the winding mode of anti-dust type provides that thefilm be wound starting from the top of the load in order to then descendtowards the base, while the anti-water winding provides that, on thecontrary, the film be wound starting from the base of the load in orderto then ascend towards the top.

In both winding modes, the film must be applied in a manner so as tofirmly block the upper cover sheet in position, in order to prevent thepenetration of the weathering agents.

In the machines of known type, the device for applying the upper coversheet comprises a portal structure, arranged above the line foradvancing the palletized load through the machine.

Upon passage of the load, and before carrying out the local winding withthe film, the application device unwinds a sheet of predetermined lengthfrom a suitable reel supported in raised position, it cuts it to sizeand lays it down on the top of the load itself.

In order to do this, the application device must be situated at theright distance from the top of the palletized load, which naturallyvaries from case to case.

Immediately after the application of the cover sheet, the load arriveson top of a rotary table, and on the top of the same load acounter-table is positioned—it too rotatable—which maintains the coversheet in the correct position in order to carry out the blockingthereof.

Subsequently, a winding head, which supports a reel of film suitable forthe lateral winding of the load, is brought close to the load itself;the winding head is rotated and the film, after having been suitablypre- stretched, is wound around the load according to the desired mode.

The above-described application device has disadvantages due, first ofall, to the fact that, as stated, it is mounted above a bulky portalstructure, which obliges various restrictions from the standpoint of thedesign of the machine layout: more in detail, its installation above thetransport line of the palletized load requires providing for necessaryspaces in the factory, and this clearly constrains the designer of theplant to make obliged choices.

In addition, equally penalizing for the designer of the plant is thefact that the application of the cover sheet must be carried out in aspecific position of the operating cycle since, as stated, theapplicator device is fixed with respect to the machine and with respectto the transit line for the palletized loads: also this circumstanceclearly and considerably limits the operating possibilities of themachine.

Another non-negligible drawback consists of the fact that the reel fromwhich the single cover sheets are obtained is supported and unwound in araised position with respect to the transport line: this constitutes aconsiderable inconvenience for the operators who must carry out reelmaintenance or substitution interventions, which can even be quitefrequent.

SUMMARY OF THE INVENTION

The aim of the present invention is to improve the state of the art.

Within such technical aim, it is an object of the present invention tomake a device for applying cover sheets on palletized loads which allowsovercoming the above-lamented drawbacks.

Another object of the present invention is to implement a device forapplying cover sheets on palletized loads that is more flexible andversatile than the devices of known type.

A further object of the present invention is to provide a device forapplying cover sheets on palletized loads which allows managing, in anoptimal manner, the space available in the production factory.

Still another object of the present invention is to make a device forapplying cover sheets on palletized loads which allows facilitating theoperations of maintenance and/or of substitution of the reel of materialfrom which the cover sheets themselves are obtained.

This aim and these objects are attained by the device for applying coversheets on palletized loads according to the present application.

The device comprises at least one support for at least one palletizedload, means for unwinding at least one reel of cover film from which aplurality of sheets to be applied on the palletized loads can beobtained, and at least one applicator member suitable for positioning,one-by-one, the cover sheets obtained from the reel on the top ofrespective palletized loads.

The applicator member comprises at least one robotic arm having at leastone operative end, with which at least one grip member is associatedthat is suitable to pick up each cover sheet unwound from the reel at atleast one edge, and to position it on the top of a respective palletizedload.

This aim and these objects are also attained by the machine for wrappingpalletized loads according to the present application.

The present application refers to preferred and advantageous embodimentsof the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of the invention will be better understood by each manskilled in the art from the following description and from the encloseddrawing tables, given as a non-limiting example, in which:

FIG. 1 is a perspective view of a machine for wrapping palletized loads,comprising the device for applying a cover sheet according to thepresent invention;

FIG. 2 is a perspective view of the machine with some parts removed forbetter clarity;

FIG. 3 is a side perspective view of the means for unwinding the reel ofcover film;

FIG. 4 is a front perspective view of the unwinding means;

FIG. 5 is a rear perspective view of the unwinding means;

FIG. 6 is a front and detailed perspective view of the members forgripping the edge of the cover film;

FIG. 7 is a rear and detailed perspective view of the members forgripping the edge of the cover film;

FIG. 8 is a plan view of a wrapping machine according to the presentinvention; FIG. 9 is a plan view of another embodiment of the wrappingmachine according to the invention;

FIG. 10 is a plan view of still another embodiment of the wrappingmachine according to the invention;

FIG. 11 is a plan view of a further embodiment of the wrapping machineaccording to the invention;

FIG. 12 is a plan view of another embodiment of the wrapping machineaccording to the invention; and

FIG. 13 is a plan view of still another embodiment of the wrappingmachine according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

With reference to the enclosed FIG. 1, reference number 1 overallindicates a device for applying cover sheets on palletized loads,according to the present invention.

As will be better clarified hereinbelow, the device 1 can be integratedin a wrapping machine M for palletized loads P, which also forms theobject of the present invention.

It is specified that in the enclosed figures, for an improvedcomprehension, the device 1 is illustrated together with the othergroups or components of the wrapping machine M in which it isintegrated; nevertheless, it is specified that the present inventionspecifically protects the device 1, also in a manner entirelyindependent from the other features of the wrapping machine M possiblyincluding such device. The device 1 comprises at least one support 2 forat least one palletized load P. More in detail, the support 2 definesthe pre-established position in which the palletized load P is situatedin order to be subjected to the application of a respective cover sheetC on the top.

Each of the palletized loads P arrives on the support 2, being movedalong a specific advancement direction A.

The aforesaid advancement direction A can for example coincide with theadvancement direction of the palletized loads P through the wrappingmachine M which—possibly—comprises the device 1.

The device 1 also comprises means 3 for unwinding at least one reel ofcover film B.

From the reel of cover film B, a plurality of the aforesaid sheets C canbe obtained, to be applied on the top of the palletized loads P.

For this purpose, the unwinding means 3 can comprise cutting members forseparating cover sheets C of the desired size.

For the sake of simplicity, the cutting members are not represented inthe figures but they can be of any type known for this specificapplication, or for similar applications.

The device 1 also comprises at least one applicator member 4.

The applicator member 4 is suitable for positioning the cover sheets C,one by one, obtained from the reel B on the top of respective palletizedloads P.

According to one aspect of the invention, the applicator member 4comprises at least one robotic arm 5.

The robotic arm 5 comprises at least one operative end 5 a, with whichat least one grip member 6 is associated.

The grip member 6 is suitable to pick up each cover sheet C unwound fromthe reel B at at least one edge D thereof, and to position it on the topof a respective palletized load P, as will be better describedhereinbelow.

The robotic arm 5 is constituted by mutually articulated portions,associated with respective rotary actuators, so as to position theoperative end 5 a in the desired points in space, and additionally so asto move the same operative end 5 a from a starting point to an arrivalpoint with the desired speed and acceleration.

The aforesaid starting point is typically constituted by the pickuppoint of the cover sheets C provided in the unwinding means 3; theaforesaid arrival point is instead typically constituted by a suitableposition in proximity to the top of the palletized load P, in order todeposit the aforesaid sheet C thereon.

The robotic arm 5 also comprises a base 5 b, opposite the operative end5 a, positioned alongside the support 2 of the palletized load P.

The base 5 b can house the means for driving and controlling the roboticarm 5.

According to one aspect of the invention, the base 5 b of the roboticarm 5 can be situated, with respect to the support 2, in the positiondeemed optimal in relation to various aspects, including the overallplanar bulk of the device 1, the modes of reaching the starting pointand the arrival point of the operative end 5 a of the robotic arm, thetrajectory that the operative end 5 a must travel in moving between theaforesaid points, and still other aspects.

According to another aspect of the invention, the grip member 6comprises a support element 7 for at least one first gripper 8 and onesecond gripper 9.

For improved comprehension, reference is made to FIGS. 4,5, in which thegrip member 6 is shown released from the robotic arm 5.

The first gripper 8 and the second gripper 9 are suitable to selectivelygrasp the edge D of the film of the reel B in at least two respectivedistinct points.

The support element 7 has elongated shape; for example, the supportelement 7 can be constituted by a section, for example made of lightmaterial.

Such section can have shape such to define seats—for example grooves orslots—for fixing the first gripper 8 and the second gripper 9 in thedesired positions, for example at a specific distance from each other.

In more detail, the support element 7 comprises at least one portion 7 aof connection to the operative end 5 a.

The connection portion 7 a can be fixed in a variable position along thesupport element 7; in this manner, it is possible to connect the supportelement 7 itself to the operative end 5 a of the robotic arm 5 in themost opportune manner, in relation for example to the particulartrajectory that the operative end 5 a must complete and with regard tothe mutual positioning of the parts.

The first gripper 8 and the second gripper 9 can be positioned at theopposite ends of the support element 7, for an improved grip of the edgeD of the film of the reel B.

According to another aspect of the invention, the grip member 6 alsocomprises a third gripper 10.

The third gripper 10 is connected to the support element 7, and isinterposed between the first gripper 8 and the second gripper 9.

In one embodiment of the invention, the grippers 8,9, 10 can bepositioned substantially equidistant from each other, for an optimalgrip of the edge D of the film of the reel B.

Each of the grippers 8,9,10—as shown in FIGS. 6,7—comprises a firstmember 11 and a second member 12, mutually movable between an openposition and a closed position for gripping the edge D of the film ofthe reel B.

FIGS. 6,7 in particular show one of the grippers 8,9,10 with the firstmember 11 and the second member 12 in closed position for gripping theedge D.

The first member 11 is fixed to the support element 7, while the secondmember 12 is movable with respect to the first member 11.

The first member 11 can be constituted by a section provided withgrooves adapted for fixing to other parts, e.g. by means of screws orother connection members. The second member 12 comprises a lever 12 aarticulated to the first member 11; the lever 12 a is articulated to thefirst member 11 substantially in central position.

At one end of the lever 12 a, a terminal 12 b is connected—which forexample is made of plastic, rubber or another suitable material—intendedfor direct contact with the surface of the edge D of the film of thereel B.

The other end of the lever 12 a is connected to an actuation member 13for rotating the lever 12 a between the open position and the closedposition for gripping the edge D of the film of the reel B.

The actuation member 13 can for example be a pneumatic actuator, havingthe cylinder articulated to the first member, and the stem articulatedto the lever 12 a. The actuation member 13 can nevertheless be ofanother type, for example an electric motor, or still other types.

The unwinding means 3 comprise means 14 for the selective locking of theedge D of the film of the reel B.

The selective locking means 14 are suitable to maintain the edge D inthe correct position in order to allow the grip member 6 to grasp it, soas to pick up a cover sheet C.

More in detail, since the film of the reel B—usually made of plasticmaterial—can be subjected to uncontrollable electrostatic attractionsthat could accidentally move it, twist it or crumple it if it was leftfree, according to one aspect of the present invention the edge D of thefilm of the reel B is firmly retained and locked while awaiting for thegrip member 6 to grasp it in order to pick up a cover sheet C.

The selective locking means 14 comprise at least one first element 15and one second element 16.

The first element 15 and the second element 16 are mutually movablebetween a position of free passage of the film of the reel B, in whichthey are at a distance from each other, to a position of locking thefilm, in which they are instead in mutual contact so as to tighten theedge D therebetween.

The first element 15 and the second element 16 have respectivecorresponding first openings 15 a and second openings 16 a.

Such first openings 15 a and second openings 16 a allow the grip member6 to grasp the edge D of the film of the reel B, in order to grasp andpick up the cover sheets C one by one.

The first openings 15 a and the second openings 16 a are respectivelymade in the first element 15 and in the second element 16, so as to matewith each other when the two elements 15,16 are in a position of lockingthe film of the reel B.

More in detail, the first element 15 comprises three respective firstopenings 15 a, while the second element 16 comprises three correspondingrespective second openings 16 a.

In each of the aforesaid first element 15 and second element 16, therespective first openings 15 a and second openings 16 a are positionedwith respect to each other substantially at the same distance at whichthe grippers 8,9,10 of the grip member 6 are positioned with respect toeach other.

This means that—as shown in FIGS. 4-7—the edge D of the reel B,interposed between the first element 15 and the second element 16, canbe freely grasped by the grippers 8,9,10 of the grip members 6 which arein fact positioned at the first openings 15 a and at the second openings16 a.

The first openings 15 a and the second openings 16 a have a widthsufficient to allow the easy insertion of the grippers 8,9,10, withoutrisk of accidental impact.

At the same time, the first openings 15 a and the second openings 16 ahave relatively limited size, so as to prevent the edge D of the reel Bfrom being twisted or crumpled accidentally and hence preventing thegrip of the grippers 8,9, 10 from being precarious or in any caseincorrect.

The selective locking means 14 are mounted on a support frame 17 for theunwinding means 3.

The frame 17 is substantially shaped as a kind of elongated tank, withinwhich the reel of cover film B is supported, in the manner betterdescribed hereinbelow.

The first element 15 and the second element 16 are supported at one ofthe edges of the frame 17, and in particular at the higher of the twoedges of the frame 17 arranged according to its long sides.

The first element 15 and the second element 16 have substantiallyplate-like shape. More in detail, the first element 15 can be completelyflat; the second element 16 can have the terminal edge 16, arrangedaccording to the longer side, raised, so as to create a constraintagainst the exit of the edge D of the film of the reel B.

In the embodiment of the invention shown in the figures, the firstelement 15 is fixed, while the second element 16 is movable with respectto the aforesaid first element 15, even if solutions could be providedin which the roles of the two elements 15,16 are reversed.

The second element 16 is rotatable around a rotation axis R parallel tothat of the reel B of cover film.

The second element 16 is associated with at least one actuator 18,adapted to rotate the same second element 16 between the position offree passage of the film of the reel B and the selective lockingposition thereof.

More in detail, in the embodiment illustrated in the figures, the secondelement 16 is associated with two actuators 18; the two actuators 18 arefor example provided at the ends of the support frame 17, but could beprovided in other suitable positions. In the embodiment illustrated inthe figures, each of the actuators 18 is of pneumatic type, andcomprises a cylinder articulated to the frame 17 (in an oppositeposition with respect to that where the first element 15 is provided),and a stem articulated to the second element 16.

In other embodiments of the invention, one or more actuators 18 ofanother type could be provided, for example comprising one or moreelectric motors, or still others.

According to another aspect of the invention, the unwinding means 3comprise at least one seat 19 for the reel of the cover film B.

In the seat 19, the reel of cover film B is placed which must be unwoundin order to obtain the single sheets C to be applied on respectivepalletized loads P.

The seat 19 is provided within the support frame 17, which as stated issubstantially shaped as a tank or, more generally, as a container openedat the top.

In one embodiment of the invention, the seat 19 could be made in amanner such to house the reel B with axis during use that is vertical.

The unwinding means 3 comprise two unwinder rollers 20,21, between whichthe film of the reel B passes, and in particular a first unwinder roller20 and a second unwinder roller 21.

The first unwinder roller 20 is rotatably supported in the frame 17, andhas the symmetry axis coinciding with the rotation axis R of the secondelement 16.

The second unwinder roller 21 is instead supported in a respectivecounter-frame 21 a which, during use, is brought close to the frame 17,as shown in particular in FIG. 5.

The unwinder rollers 20,21 can both be idle, or at least one of thesecan be associated with respective friction means, or adjustable brakingmeans, or a respective rotation actuation means.

At least one from among the unwinder rollers 20,21—e.g. the secondunwinder roller 21—can be provided with surface parts in relief made of(or covered with) high friction coefficient material, e.g. rubber, for amore effective driving of the film.

The seat 19 also comprises at least two support rollers 22,22 a, withparallel axes, on which the reel of cover film B can roll.

The support rollers 22,22 a are rotatable in the bottom of the supportframe 17. During use, the reel B is abutted against the support rollers22,22 a, and the edge D thereof is passed between the unwinder rollers20,21, in order to then be inserted between the selective locking means14.

As stated, at least one of the two unwinder rollers 20,21, can bemotorized in order to facilitate the unwinding of the reel B;alternatively, the unwinding of the reel B can be directly obtained dueto the traction exerted on its edge D by the grip member 6 of therobotic arm 5.

According to one aspect of the invention, the seat 19 for the reel B canbe movable between at least one operative position and one substitutionor maintenance position, or waiting position.

In the aforesaid operative position, the seat 19 of the reel B isarranged in an optimal manner in order to allow the grip member 6 topick up the single sheets C. In the substitution/maintenance/waitingposition, instead, the seat 19 of the reel B is arranged so as to allowoperators to easily and safely carry out their possible interventions.

In addition, at such substitution/maintenance/waiting position of thereel B, suitable protections 23 are provided for the operators.

In this manner, the operators, in executing their work, are protectedfrom the movements of the robotic arm 5, which could be dangerous fortheir safety.

According to another aspect of the invention, the unwinding means 3 cancomprise at least two seats 19 for two respective reels B.

As will be better described hereinbelow, this allows ensuring operatingcontinuity of the device 1 in the case of depletion or jamming of one ofthe reels B: in other words, if one of the reels B is not available forany reason, the robotic arm 5 can pick up sheets C from the other reelB, so as to not interrupt the production cycle. The two seats 19 for therespective reels B can for example be facing or superimposed.

In particular, in the embodiment of the invention illustrated in FIGS.1-8, the device 1 comprises two seats 19 arranged facing each other, andeach of these is movable between the aforesaid operative andsubstitution/maintenance/waiting positions.

As shown, for example, in FIG. 1, each of the two seats 19 of the reelsB can be slidable between said operative andsubstitution/maintenance/waiting positions: in the operative position,one of the seats 19 or the other is situated in the vicinity of therobotic arm 5, while in the substitution/maintenance/waiting positionone of the seats 19 or the other is situated within a protection 23shaped for example like a cage, in which the operator can work inmaximum safety conditions.

According to a further aspect of the invention, and as illustrated inthe details of FIGS. 4,5, the two seats 19 for the respective reels Bhave the respective support frames 17 slidable along a same basestructure 24.

The base structure 24 comprises respective parallel guides 25, alongwhich the two support frames 17 are slidable.

The base structure 24 is then installed in a manner such that oneportion thereof is situated within the protection 23, hence in thesubstitution/maintenance position, and another portion outside the same,in the operative position.

The sliding of each of the two frames 17 can be carried out in anautomated manner, for example by means of respective linear actuators26, or it can even be carried out manually.

In other embodiments of the invention, a greater number of seats 19 canbe provided for respective reels B of cover film.

For example, in the embodiment of FIG. 9, the device 1 comprises fourseats 19 for respective reels B: with this solution, in addition toensuring the necessary operating continuity in case of damage/failure orjamming, a greater versatility of use is also allowed in order toquickly and easily vary the size and/or type of film used for thecovering.

In the embodiments schematically shown in FIGS. 8,9, the seats 19 arearranged so as to be slidable in a direction orthogonal to theadvancement direction A of the palletized loads P.

In other embodiments, the seats 19 could be arranged differently withreference to the aforesaid advancement direction A.

For example, in the embodiments of FIGS. 10-13, the seats 19 arearranged with the axes of the respective reels B parallel to theaforesaid advancement direction A, and also in this case they can beside-by-side or superimposed in order to limit the bulk.

The operation of the device 1 is entirely intuitive in light of thatdescribed above. Upon reaching a palletized load P on the support 2, therobotic arm 5 approaches the unwinding means 3.

Simultaneously, the edge D of the reel B of cover film is tightened bythe selective locking means 14.

More in detail, the aforesaid edge D is interposed between the firstelement 15 and the second element 16: the latter are brought into alocking position of the film of the reel B, so as to firmly retain theedge D while awaiting the arrival of the grip member 6.

The grip member 6 then approaches the unwinding means 3, with therespective grippers 8,9,10 in open position.

The grippers 8,9, 10 are then brought to the first, second openings 15a, 16 a, so as to interpose the edge D between the respective first,second members 11,12.

The first, second members 11, 12 are then mutually brought closetogether, being carried into a gripping position of the edge D of thefilm of the reel B.

After having grasped the edge D, the grip member 6 is moved away so asto unwind, via traction, a portion of film of the reel B of suitablelength.

The cutting members of the unwinding means 3 are then driven; a coversheet C is in such a manner separated from the reel B. Such cover sheetC is then—as shown in the same FIGS. 1,2—placed on the top of thepalletized load P.

The grip member 6 releases the sheet C, and the cycle for applying a newsheet C is repeated exactly as described.

If the film of the reel B is depleted—and if the unwinding means 3comprise multiple seats 19 for respective reels B—the seat 19 bearingthe depleted reel B is carried into substitution/maintenance/waitingposition, while the other seat 19, bearing a full reel B, is broughtinto the operative position and is accessible to the robotic arm 5.

The same occurs if the material for making the sheets C must be varied,or if sheets C must be made of difference size, hence obtainable fromdifferent respective reels B.

The invention as conceived allows attains important technicaladvantages.

First of all, the robotic arm 5 can be freely placed in the mostsuitable position with respect to the support 2 for the palletized loadP; this ensures greater freedom for the designer of the packaging plant,since there are no constraints that require the device 1 to be in apredetermined position, as occurs for the machines of known type-One ofthe main attained advantages is the possibility to reduce the planarbulk of the packaging plant, or to adapt it to the available spaces.

Another advantage consists of the fact that the robotic arm 5 can besituated in the most suitable position in relation to the specificrequirements of a specific wrapping work, for example if it is necessaryto carry out an anti-water or anti-dust wrapping, or for reducing to aminimum the travel that the load P carries out between the applicationof the sheet C and the subsequent lateral wrapping, or for still otherneeds, such as reducing the operating times of the wrapping machine.

In addition, the reel B of cover film is now situated in a position thatis much more convenient and accessible for the operators with respect towhat occurs in the apparatuses of known type, e.g. in order to performmaintenance and/or substitution operations.

Particularly efficient and advantageous is the picking up of the coversheets C obtained from the reel B, due to the selective locking means 14which cooperate with the grip member 6, preventing possible accidentalmovements of the edge D of the cover film.

As mentioned above, also forming the object of the present invention isa wrapping machine M for palletized loads P, comprising at least onedevice 1 for applying cover sheets having the above-describedcharacteristics.

The machine M comprises a line 27 for advancing the palletized loads P;in particular, the palletized loads P advance between an inlet 28 andoutlet 29 that are opposite each other.

The advancement line 27 can for example be of the type with rollers, orof any other equivalent type.

In addition, the machine M comprises at least one apparatus 30 forwrapping the palletized loads P.

The winding apparatus 30 has the function of winding a wrapping filmaround the lateral surface of the palletized load P, so as to lock thecover sheet C applied by the device 1 in position.

The winding apparatus 30 comprises at least one winding head 31; inturn, the winding head 31 supports a reel for wrapping film around thepalletized loads P. The winding apparatus 30 can for example comprise arobotic winding arm which carries the head 31 at its operative end, asshown in the embodiments of FIGS. 1-10 and 12,13.

The winding apparatus 30 can also be of another type, for example of thetype comprising a kind of column base, which is vertically extended andalong which the winding head 31 slides, in order to wind the film aroundthe palletized load P from top to bottom or from bottom to top, inrelation to the requested winding mode.

The latter solution is provided in the embodiment of the machine M shownin FIG. 11.

The machine M also comprises at least one rotary table 32.

The rotary table 32 is rotatable around an axis that is vertical duringuse.

The rotary table 32 is, more in detail, provided along said advancementline 27 between the inlet 28 and the outlet 29.

Also the rotary table 32 comprises rollers which, in a specific positionof the table 32 itself, have the respective axes parallel to those ofthe advancement line 27, so as to obtain the necessary continuity thatallows the translation of the palletized loads P.

The machine M also comprises a counter-table 33, with relative supportmeans 34, opposite the rotary table 32 and adapted to be positioned onthe top of the palletized load P so as to maintain it in the correctequilibrium position during the rotation imparted by the table 32, andthus also to maintain in the suitable position the cover sheet C appliedon the load P by the device 1.

The support 2 for the palletized load P is provided along theadvancement line 27. More in detail, the support 2 is constituted by aspecific zone of the advancement line 27, i.e. the most suitable zonewhere to deposit the cover sheet C on the top of the palletized load P,in order to then perform the lateral wrapping of the same in a quick andeasy manner.

For example, the zone of the advancement line 27 at which theapplication of the cover sheet C occurs can be that which immediatelyprecedes the arrival of the load P on the rotary table 32.

The distance between such application zone and the rotary table 32 canbe reduced to the minimum, since the robotic arm 5 can also follow theload P while this advances towards the table 32.

FIGS. 8-13 schematically illustrate, in plan view, various possibleembodiments of the wrapping machine M comprising the application device1 according to the present invention.

In particular, in the embodiments of FIGS. 8-10—in which the windingapparatus 30 comprises a robotic winding arm—the apparatus 30 and therobotic arm 5 are positioned on the same side with respect to theadvancement line 27.

Also the unwinding means 3 are positioned on the same side where therobotic arm 5 is situated.

Since the robotic arm 5 can be placed in various positions, it can beplaced for example in the immediate vicinity to the unwinding means 3,and also close to the support 2 for the palletized load P (i.e. close toa specific zone of the advancement line 27).

In this manner, the action radius of the robotic arm 5 is circumscribedat a well-defined zone of the machine M: this allows considerablylimiting the planar bulk of the machine M itself, without howeverlimiting the functional capacities thereof.

In the embodiment of FIG. 11, the machine M comprises a windingapparatus 30 comprising a kind of column base, which is verticallyextended, along which the winding head 31 slides.

This winding apparatus 30 solution has a lower planar bulk than thesolution with robotic arm, but it also has lower versatility of use.

In this case, the robotic arm 5 of the device 1 is positioned on theopposite side with respect to the advancement line 27.

In addition, the means 3 for unwinding the reel B of the cover film arepositioned at the same side where the winding apparatus 30 is situated.

Therefore, in this case, the action radius of the robotic arm 5 iscompletely superimposed on the advancement line 27: in this manner it ispossible to obtain a solution with very limited planar bulk especiallyaccording to the direction orthogonal to the advancement direction A ofthe palletized loads P.

In the embodiments illustrated in FIGS. 12, 13, finally, the machine Mcomprises a winding apparatus 30 of the type comprising a robotic armcarrying the respective winding head 31.

In addition, in both of these embodiments, the means 3 for unwinding thereel B of cover film and the robotic arm 5 of the device 1 arepositioned on the same side with respect to the advancement line 27, andboth on the opposite side with respect to the winding apparatus 30.

For example, with respect to the embodiments of FIGS. 8,9, thisarrangement allows reducing the planar bulk of the machine M at least ata section of the advancement line 27.

The operation of the wrapping machine M, comprising the applicationdevice 1, is therefore the following.

Each palletized load P follows the advancement line 27 and reaches therotary table 32.

The robotic arm 5 picks up a relative cover sheet C from the unwindingmeans 3, and places it on the top of the palletized load P.

The times and modes of positioning the cover sheet C on the palletizedload can vary in relation to the lateral winding mode of the load Pitself.

Indeed, according to the anti-dust winding mode, the lateral wrappingfilm is wound by the head 31 starting from the top of the load P, thendescending towards the base, while the anti-water winding on thecontrary provides that the film be wound by the same head 31 startingfrom the base of the load P, then ascending towards the top.Consequently, the movements that the robotic arm 5 executes for placingthe sheet C on the load P can be different in relation to the winding tobe carried out.

More particularly, in the case of winding of anti-dust type, the coversheet C can be positioned on the top of the palletized load P while thelatter is still moving, i.e. it is still situated in the step ofadvancing towards the rotary table 32.

Indeed, as stated this winding mode provides that the lateral film beapplied starting from the top of the load P, hence the sheet C isimmediately immobilized by the lateral film itself as soon as thetop-to-bottom winding has started.

Therefore, in this case the robotic arm 5, bearing the sheet C,accompanies the advancement of the load P on the line 27, and providesto apply the sheet C itself on the top thereof: normally the load P ismoved on the advancement line 27 with relatively low speeds, hencecompatible with such operation.

More in detail, the robotic arm 5 can be driven so as to be moved inopposite direction with respect to that of advancement of the load P, soas to place the sheet C on the top of the load P itself starting fromthe front side and proceeding towards the rear side, with reference tothe aforesaid advancement direction.

In the case of anti-water winding, instead, it can be opportune orconvenient to apply the sheet C on the top of the palletized load P withlateral winding already started, in order to ensure that there are nointerstices between the sheet C and the lateral film, through whichmoisture could penetrate.

In this case, therefore, according to a specific operating mode, inorder to obtain an anti-water covering the lateral film is woundstarting from the top and by carrying out a first preparatory descent.

Subsequently, once the base of the palletized load P has been reached,the winding continues from bottom to top, and at a certain point it isstopped in order to allow the application of the sheet C.

More in detail, the counter-table 33 is lifted and the robotic arm 5provides to position the sheet C on the top of the palletized load P,temporarily immobile.

Following this, the winding of the lateral film restarts, making thenecessary number of revolutions—e.g. two—in order to block the sheet Cin position.

The winding mode of anti-water type requires longer operating times thanthose required by the anti-dust mode: for this reason, the use of therobotic arm 5 is particularly advantageous since it allows applying thesheet C on the top of the load P in a particularly quick and precisemanner, i.e. at the moment when the lateral winding is stopped andbefore the final sheet C fixing revolutions have been carried out.

Also forming the object of the present invention is a method forwrapping a palletized load P according to the previously describedoperating steps.

The method comprises the steps of providing at least one support 2 forat least one palletized load P, providing means 3 for unwinding at leastone reel of cover film B, from which a plurality of sheets C can beobtained that are to be applied on the palletized load P, and providingat least one winding apparatus 30, suitable to wind a wrapping filmaround the lateral surface of the palletized load P.

According to the invention, the method also comprises the steps ofproviding at least one applicator member 4 suitable to position a sheetC obtained from said reel B on the top of the palletized loads P, inwhich the applicator member 4 comprises at least one robotic arm 5having at least one operative end 5 a with which at least one gripmember 6 is associated.

The method provides for a step of grasping the edge D of the reel B bymeans of said grip member 6, so as to pick up a sheet C, and ofpositioning the sheet C on the top of the palletized load P by means ofthe robotic arm 5.

The method then provides for a step of winding the film around thepalletized load P, so as to block the sheet C in the correct coverposition.

It was thus seen that the invention attains the proposed objects.

The device 1 and the machine M according to the present invention allowobtaining greater flexibility and versatility both regarding design anduse, since the robotic arm 5 can be situated in the most suitableposition in relation to the layout needs and planar bulk, as well as inrelation to the function needs of application of the cover sheet C onthe top of the palletized load P.

More in detail, the robotic arm 5 is particularly advantageous since itallows effectively carrying out the wrapping of the palletized loads Paccording to all the possible winding modes, for example according tothe most widespread anti-water and anti-dust modes.

Indeed, the mobility of the robotic arm 5 allows positioning the sheet Con the top of the palletized load P at the most opportune time inrelation to the specific winding mode to be executed, reducing theoperating times of the wrapping machine M.

In addition, these results are obtained with a particularly versatileand advantageous solution from the standpoint of the layout of thewrapping machine M.

Moreover, the operations of substitution of the reel B of cover film oreven of maintenance thereof are considerably simplified, since theunwinding means 3 are now positioned in a manner so as to be easilyaccessible to the operators, and in zones provided with protections 23from the action radius of the robotic arm 5. The present invention wasdescribed according to preferred embodiments, but equivalent variantscan be conceived without departing from the protective scope offered bythe following claims.

1. A device for applying cover sheets on palletized loads, comprising at least one support for at least one palletized load, means for unwinding at least one reel of cover film from which a plurality of sheets to be applied on the palletized loads can be obtained, and at least one applicator member adapted to one-by-one position the cover sheets obtained from said reel on the top of respective palletized loads, wherein said applicator member comprises at least one robotic arm having at least one operative end with which at least one grip member is associated, said grip member being adapted to pick up each cover sheet unwound from said reel at at least one edge, and to position it on the top of a respective palletized load, wherein said robotic arm comprises a base, opposite the operative end, positioned alongside the support of the palletized load, and wherein said robotic arm can follow the load while said load advances.
 2. The device according to claim 1, wherein said unwinding means comprise at least one seat for at least one respective reel of cover film, comprising at least two unwinder rollers with parallel axes, said unwinder rollers being idle, or at least one of these being associated with respective friction means or with respective rotation actuation means.
 3. The device according to claim 2, wherein said seat is made in a manner so as to house said reel with axis that is vertical during use.
 4. The device according to claim 3, wherein said seat is movable between at least one operative position and one substitution/maintenance/waiting position, at which protections are provided for the operators.
 5. The device according to claim 2, wherein said unwinding means comprise at least two side-by-side or superimposed seats for respective reels, so as to be able to ensure operating continuity of the device in the case of wearing out or jamming of one of these seats.
 6. The device according to claim 1, wherein said robotic arm comprises a base, opposite said operative end, positioned alongside said support of the palletized load.
 7. The device according to claim 1, wherein said grip member comprises a support element for at least one first gripper and one second gripper, adapted to selectively grasp the edge of each sheet in at least two respective separate points.
 8. The device according to claim 7, wherein said support element has elongated shape and comprises at least one portion of connection to said operative end, said first gripper and second gripper being positioned at the opposite ends of said support element.
 9. The device according to claim 8, wherein said grip member comprises at least one third gripper, associated with said support element, and interposed between said first gripper and second gripper.
 10. The device according to claim 1, wherein said unwinding means comprise means for the selective locking of the edge of each cover sheet unwound from said reel, adapted to maintain said edge in the correct position in order to allow said grip member to grasp it.
 11. The device according to claim 10, wherein said selective locking means comprise at least one first element and one second element mutually movable between a position of free passage of the edge of the reel, in which they are separate from each other, and position of locking the edge of the reel B, in which they are in mutual contact so as to shut the edge between them.
 12. The device according to claim 11, wherein said first element and second element are covered with respective corresponding first openings and second openings in order to allow said grip member to grasp the edge of the reel.
 13. The device according to claim 11, wherein said first element and second element have substantially plate-like shape, said first element being fixed and said second element being movable with respect to said first element.
 14. The device according to claim 13, wherein said second element is rotatable around a rotation axis parallel to the symmetry axis of said reel, and is associated with at least one actuator adapted to rotate said second element between said position of free passage of the edge of the reel and said position of locking the edge.
 15. The device according to claim 14, wherein said unwinding means comprise at least one tightener roller having axis that coincides with said rotation axis, around which the cover film unwound from said reel is wound and held in position by said selective locking means.
 16. A machine for wrapping palletized loads, comprising at least one device for applying cover sheets according to claim
 1. 17. The machine according to claim 15, comprising a line for advancing palletized loads between an inlet and an outlet, said advancement line comprising said support for said palletized load, at least one winding apparatus carrying at least one winding head which in turn supports at least one reel for wrapping film around the palletized loads.
 18. The machine according to claim 16, wherein said winding apparatus and said robotic arm are positioned on the same side with respect to said advancement line, or on opposite sides.
 19. The machine according to claim 17, wherein said robotic arm and said unwinding means are positioned on the same side with respect to said advancement line, or on opposite sides.
 20. A method for wrapping a palletized load, comprising the steps of providing at least one support for at least one palletized load, providing means for unwinding at least one reel of cover film, from which a plurality of sheets to be applied on the palletized load can be obtained, providing at least one winding apparatus adapted to wind a wrapping film around the lateral surface of the palletized load, comprising the steps of providing at least one applicator member adapted to position a sheet obtained from said reel on the top of the palletized load, said applicator member comprising at least one robotic arm having at least one operative end, with which at least one grip member is associated, and a base opposite the operative end and positioned alongside the support of the palletized load, grasping the edge of the reel by means of said grip member, so as to pick up a sheet, positioning said sheet on the top of the palletized load by means robotic arm, said robotic arm having the possibility of following the load while said load advances, wrapping the film around the palletized load so as to block the sheet. 